// 基础类型
// null, undefined, symbol, void, boolean
const count: number = 123
const teacherName: string = 'ykk'

// 对象类型
const teacher: {
  name: string
  age: number
} = {
  name: 'yk',
  age: 18,
}

const numbers: number[] = [1, 2, 3] // number为数组，元素为number类型

class Person {}

const y: Person = new Person() //y必须为 Person类对应的一个对象

const getTotal: () => number = () => {
  return 123
}
